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# Questions tagged [tree]

A tree is a graph in which there is exactly one path between any two nodes. It is often used as a hierarchical data structure.

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I'm new on C++ and OOP. I wrote the following QuadTree implementation (I didn't wrote the remove object part yet). please take a look on it and provide feedback, mainly about C++ OOP design, ...
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### Port Node and TreeBuilder from Python to C++

I am trying to port a TreeBuilder Python class to C++, keeping the structure as close as possible to the original. Here is a simplified Python version: https://onlinegdb.com/I4dg0hCtg The purpose of ...
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### Leet Code: 236. Lowest Common Ancestor of a Binary Tree. First version

Trying my hand at Leet 236 Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is ...
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### Leet Code: 236. Lowest Common Ancestor of a Binary Tree

Trying my hand at Leet 236. Given a binary tree, find the lowest common ancestor (LCA) of two given nodes in the tree. According to the definition of LCA on Wikipedia: “The lowest common ancestor is ...
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### Traversing a 2D array with a tree

In order to help me solve the December Jane Street puzzle "Die Agony" I wrote a quick and dirty script to manually brute-force through the thing and do the calculations for me. I then tried ...
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### Converting String to Binary Hash Tree

I've written a pretty basic algorithm to convert a string to a binary hash tree of its characters, where each character represents a leaf node. The hash tree itself is being stored in a vector. If the ...
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### Implementation of a market that matches bids to offers

This is my task: Each line in the file can be one of the following: Updates to the limit order book in the following format: ...
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### Java pathfinding in general trees - Part 2/4: algorithms

Java pathfinding in general trees - Part 1/4: model classes Java pathfinding in general trees - Part 2/4: algorithms (this post) Java pathfinding in general trees - Part 3/4: demonstration Java ...
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### Java pathfinding in general trees - Part 1/4: model classes

Java pathfinding in general trees - Part 1/4: model classes (this post) Java pathfinding in general trees - Part 2/4: algorithms Java pathfinding in general trees - Part 3/4: demonstration Java ...
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### function to group data by parent branches

I wrote this function to take database output like from PDO's fetchAll(PDO::FETCH_ASSOC) and turn it into a tree. For small datasets it works well. However, when ...
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### C++ B-Tree serialization/deserialization

Yesterday I wrote a serialization/deserialization for my B-Tree library. Since the code for whole tree is too large to upload here, I'll upload only serialization/deserialization and node class ...
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### Traverse a list of tree nodes

I am wondering if there is a better way to traverse a list of trees. Here is my current algorithm: Collect the parent IDs in a Map Traverse all the groups and find ones where their ID is not in the ...
1 vote
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### Java - Select the maximum integers from sliding windows over an array

So I have the following algorithm. Given an array A[0 ... n - 1] and the window length w, compute all the windows ...
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1 vote
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### Binary Search Tree implementation in C++ with templates

Im implementing a BST using templates and dynamic memory, here is my attempt: This is the BSTNode.hh ...
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### Simple non balancing indexed binary search tree

The following code represents a simple indexed binary search tree of integers. The insert method inserts an int. The indexed lookup looks up the ith smallest element (0 indexed). I'm trying to write C+...
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1 vote
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### Decision Tree for classification tasks in Python

I've decided to implement the ID3 Decision Tree algorithm in Python based on what I've learned from George F. Luger's textbook on AI (and other secondary readings). As far as I know, the code is ...
1 vote
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### Replacing multiple substrings in C#

There is a String.Replace method in C# and it is 1-1 mapping replacing operation, i.e. single Unicode character / string source replaced with another single Unicode ...
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### Simple Merkle Tree

Discussion I just started learning about Merkle Trees and wanted to get some practice by attempting to implement a very simple Merkle Tree. The constructor for the tree takes some type of hash ...
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1 vote
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### Comparing two general LCA algorithms in Java

Now I have two algorithms solving a problem: given a general (multi-way) tree, and any array of node names, find the the node that is the deepest common ancestor. ...
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### Populate TreeView with arbitrary depth from DataTable

I have a DataTable with id, parent, label columns and want to populate a TreeView with it. I'm new to c# and as far as I understand, there is no ready solution for it, unlike some other languages. So ...
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### Barnes-Hut $n$-body simulation (3D) in C++

I have implemented the Barnes-Hut algorithm for $n$-body-simulations (in this case "sort-of" 3D-gravity - see below). I'd appreciate any comments for improving my code (especially ...
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1 vote
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### Comparing a prefix tree against a HashSet of strings in Java

Here, I have made an attempt to find out whether a prefix tree is any more efficient than a simple java.util.HashSet<String>. See what I have: ...
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### Tree for PowerShell

This Module started as a fun coding exercise designed to emulate the tree command and also calculate the size of each folder based of the files size of that folder (...
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### A Lowest Common Ancestor (LCA) Tree Algorithm

My implementation of the lowest common ancestor (LCA) algorithm for my tree data structure. I selected the non-preprocessed (naïve) implementation for this first implementation. Support for any number ...
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### is my Prim's MST implementation terse enough?

I did research because I want to learn Kruskal's and Prim's MSTs. I did research and after a solid understanding, I went to my textbook and got their libraries: https://algs4.cs.princeton.edu/code/...
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### Leetcode 662. Maximum Width of Binary Tree Javascript FlatMap attempt - Time Limit Exceeded

Problem Statement: Given the root of a binary tree, return the maximum width of the given tree. The maximum width of a tree is the maximum width among all levels. The width of one level is defined as ...
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### Find ALL duplicate subtrees. using recursion

This is just a practice exercise, I'm trying to understand dynamic programming as deeply as I can. I solved this using recursion, though I am not sure if it will always work. If anyone could tell me a ...
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1 vote
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### How does one write DFS in python with a Deque without reversed for Trees?

I have implemented a correct version of DFS (with comments explaining the implementation): ...
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### Building a tree containing all permutations of arithmetic expressions given some numbers

Given any series of numbers, for example 1,2,3,4,5 and given the arithmetic operands + - * / including parenthesis, what would be the most optimal way to build a tree that contains all permutations ...
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### AVL Tree in C Criticism

I have made an AVL tree in C and coded the basic functionality of insertion, deletion, and search. I would love some criticism on my implementation especially on the insertion and deletion section of ...
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### Monte Carlo Tree Search Optimization and Loss Prevention

I'm working on an implementation of Monte Carlo Tree Search in Swift. It's not bad, but it could be better! I'm principally interested in making my algorithm: faster (more iterations/second) ...
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### Haskell Dynamic Programming on a Tree

Here is my shot at Homework 8 of CIS-194 (from Spring '13). The problem is about a hierarchy of employees at a company (a tree), each node being of type Employee, ...
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### Pretty print a tree from minimal data input

I'm currently working on an uncrafting tool for minecraft and got a neat output working that shows all the materials needed in a tree. I wonder if the code used to print that tree could be improved ...
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### Implementation of binary tree traversal

Based on what i understood of Binary Tree, queue and recursion I implemented this Breadth First Search algorithm as follows. Do you have any suggestions to improve (in term of readability, good ...
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### Code structure for tree representation with multiple types (classes) of nodes and circular dependencies

I am developing a piece of code around a tree structure. The tree can do a few things - one of them being its ability to serialize & de-serialize its data. There are multiple different types of ...
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1 vote
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### Set operations on a tree / Hierarchical set class

Initially, I posted this question on StackOverflow. I wanted to know if there's an existing library that implements the concept I have in mind, which is the following. I want to define a hierarchy/...
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### Counting unival subtrees - Follow Up

This code is a revised version of the implementation which asked for an advice on improvement. Original post here: Counting unival subtrees Credits to: [Deduplicator], [Reinderien], [Toby Speight], [...
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### Implementing an autocomplete system

Question: Implement an autocomplete system. That is, given a query string s and a set of all possible query strings, return all strings in the set that have s as a prefix. For example, given the query ...
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### Lowest Common Ancestor in Binary Tree (Iterative)

In the below code I've implemented a method to find the lowest common ancestor of a binary tree. This is an iterative approach using this pseudocode. Please suggest any improvements that can be made. <...
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### A Concurrent Tree implementation with consistent snapshot capability

I have a tree in my application from which I need to periodically take a snapshot. I've been using locks so far, but after running into a few deadlock issues I decided to create a lock-free ...
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### Check if a binary tree is symmetric in Python

I have solved the following Leetcode problem. Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is symmetric....
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### Construction and search of Kd-Tree in c++

I am not very fluent in C++ and want to construct a Kd-Tree in C++ based on this paper Efficient Locally Weighted Polynomial Regression Predictions, to use it to conduct some fast implementations of ...
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### HackerRank - Binary tree to compute the Nth power of natural numbers that sum up to X

I'm trying to solve this challenge on HackerRank. In short, given x and n, I have to determine how many ways I can pick numbers ...
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### Using smart pointers to construct Binary Search Tree

I have three main questions: Am I using std::unique_ptr correctly here? Using std::move and ...
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### C++ : Red-Black Tree with std::unique_ptr

This is my C++ implementation of a Red-Black Tree, referring the CLRS book. Half for fun, half for studying. As implementing child node, I chose std::unique_ptr ...
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### Find Invalid User Relationships in User to Manager Map (validate map as valid tree structure with no circular relationships)

We have a new service where an admin can upload a spreadsheet of new users they want to add to our application. During our processing we make a union map of all the users both existing and new ...
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### Linked tree built from (n) leaves

Firstly, here is the relevant code. It is written in kotlin. ...
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### Red-Black Tree Implementation in Python

I'm wondering if there are better practices, and optimizations I could make on my code, to do things easier/faster. I have added comments, in many places in the code, to make understanding easier. <...
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### XML Tree Reformatter requested code. C#

So this is a post as per request in a different post on stack overflow: https://stackoverflow.com/questions/62412713/why-does-my-c-sharp-xml-code-only-work-when-i-enumerate-variable-enumerable. The ...
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